You've probably heard the old health adage "Don't eat it if your grandmother wouldn't recognize it." The idea being: toss the chemical-laden modern marvels in favor of natural, unprocessed foods for better health. The paleo diet takes things a couple of generations (OK, a lot of generations) further.

Named for the Paleolithic Era (the period ranging from 2.5 million to 10,000 years ago), the paleo diet consists of the food groups that were available to our hunter-gatherer ancestors and it forgoes many of our relatively modern agricultural comforts. It touts some major health benefits, too, including weight loss and prevention of chronic diseases.

Whether you choose to go full-on caveman and follow a strict paleo diet or just cut back on processed foods, there's a lot to be learned from how our ancient ancestors ate. Here, discover what you can eat when you "go paleo," how it might benefit you, and some troubleshooting tips.

The basics: What is the paleo diet, and where did it come from?

We've improved on a lot of things since our cave-dwelling days (hello, Netflix and sleeping on mattresses indoors), but cavemen may have had the whole "healthy diet" thing figured out.

But what exactly does it mean to eat like a caveman? Essentially, the paleo diet rules dictate that you can eat no grains, no dairy, no soy or other legumes, no refined sugars, and obviously nothing highly processed that contains any of those ingredients. Even white potatoes are off limits, depending on how strictly you follow the plan.

First popularized by Dr. Loren Cordain in his book The Paleo Diet, this way of eating is currently followed by about 7 percent of Americans. Everyone from LeBron James to former President George Bush has reportedly dabbled with this caveman-inspired diet, and it even topped Google's list of most searched diets in 2013. With meal kit delivery companies offering paleo diet plans and grocery stores stocking shelves full of paleo snacks, it has never been easier to eat like a caveman.

So, why ditch foods that are typically considered healthy like whole grains and legumes? Many people who subscribe to the paleo diet believe we did not actually evolve to eat many of the foods in our "modern" diet. Agriculture, after all, is a relatively new development for our species, and for millions of years, our ancestors survived by eating only what they could scour from the earth.

The agricultural revolution marked a huge turning point for society but also our health. Many scientists believe a discordance between our evolutionary diet and the modern diet is the root of chronic diseases like diabetes, cancer, and cardiovascular disease. In fact, studies of indigenous populations following a more traditional paleo lifestyle have found significantly lower levels of heart disease and insulin resistance. Basically, our bodies just weren't meant to eat this way, and modern staples like grains and dairy may be what's behind many of our current health problems.

But it hasn't always been this way. For millions of years, humans were much more likely to die of a communicable disease than a chronic disease. Our cave-dwelling ancestors weren't dying of diabetes or heart disease, and they certainly weren't overweight. The main goal of the paleo diet and paleo lifestyle is to prevent these modern chronic diseases by nourishing our bodies with the fuel that helped us survive, and thrive, for almost all of human history. The paleo diet goes back to basics, promoting an unprocessed, whole-foods-based diet rich in protein, fiber, and good fats.

So, what exactly can you expect if you swap your modern diet in favor of a diet fit for a caveman? For starters, you'll probably lose some weight. Although weight loss is not the primary goal of the paleo diet, it is a welcome side effect. Studies have confirmed that the paleo diet can be more effective than conventional low-fat diets for weight loss. This may be due to the elimination of most added sugars and processed foods that tend to be loaded with calories and fat. Notably, it seems the paleo diet is especially effective for reducing belly fat, the most harmful kind of fat, that can lead to diabetes and other weight-related hormonal issues.

But does the paleo diet deliver on its proposed chronic-disease-fighting promises? You bet. Although the paleo diet in modern times is fairly new, meaning there are limited long-term studies, it has been shown to reduce risk factors for many common chronic health conditions. In one study comparing the paleo diet to the Mediterranean diet (often considered the optimal way of eating), in patients with heart disease, those following the paleo diet saw significantly greater improvements in blood glucose tolerance. Meaning: The paleo diet may help reduce the risk of developing diabetes.

Another study found that the paleo diet can be as effective as the Mediterranean diet for reducing signs of inflammation and oxidative stress, important biomarkers for cancer and chronic disease. And when it comes to heart health, the paleo diet came out on top for improving triglycerides, systolic blood pressure, and HDL cholesterol as compared to a diet based on our current dietary guidelines.

While more studies are still needed, it certainly seems that the paleo diet is a healthful way of eating (as long as you feel good doing it) that's stood the test of time for a reason.

Getting started: What to eat (and avoid) on a paleo diet.

What to eat on the paleo diet.

Although anthropologists are still debating the details of exactly what our ancestors ate, the common consensus for the paleo diet is as follows: high protein from quality animal sources, high fiber from nonstarchy veggies, some carbs from fruits and starchier veggies, and plenty of healthy fats. Here are some specific foods that are allowed on the paleo diet:

Coffee, tea, and herbal tea are also allowed, and you should also drink plenty of water. Technically most alcohol is not considered paleo, but if you are looking to indulge in moderation, our experts agree that red wine and tequila rank among the healthiest types of alcohol.

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What to avoid on the paleo diet.

Obviously processed foods are off limits, but what other foods would be unrecognizable to our cavemen ancestors? This diet is pre-agriculture, so you'll want to avoid the following:

grains

dairy

legumes (beans, lentils, soy, peanuts)

refined sugars

artificial sweeteners

highly processed vegetable oils (corn oil, soybean oil)

most processed foods, including anything containing the above ingredients

A typical day's menu.

Here's an example of what you can eat on a typical day of a paleo diet:

Breakfast: two eggs, half an avocado, Brussels sprout hash

Lunch: grass-fed beef patty in a lettuce "bun," side of sliced carrots and bell peppers

Snack: walnuts and blueberries, or some high-quality jerky

Dinner: pan-seared salmon over cauliflower rice and roasted veggies

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Some limitations and considerations for the paleo diet.

Although there are many health benefits to following this way of eating,functional medicine practitioner Mark Hyman, M.D., warns that "some use the paleo philosophy as an excuse to eat too much meat and too few plant-based foods."

Instead, he advocates a healthy mix of a plant-based vegan diet and a back-to-basics paleo diet, called the pegan diet. Essentially, prioritizing fiber-rich antioxidant-packed vegetables while ditching processed grains and added sugar, can help ensure you reap all of the anti-inflammatory disease-fighting powers of this ancient diet.

Another thing to watch out for: paleo flu. Also known as the "low-carb flu" and the "keto flu," some of the symptoms you can expect from transitioning to a refined-grain-free diet include headaches, fatigue, and brain fog. As your body adjusts to using protein and fat as its main fuel sources rather than a steady stream of glucose from grains and refined carbs, you may experience some of these not-so-great side effects.

However, unlike the keto diet, you don't necessarily have to go low-carb on paleo. Just be sure to consume your carbs from healthy, non-grain sources such as squash, sweet potato, or any type of fruit. Staying hydrated can also support your body's detoxification mechanisms and help ward off these symptoms.

It feels like there are a million different eating styles to choose from these days (paleo, keto, vegan, and intermittent fasting, just to name few), and what works for one person may not necessarily work for another. So, if you're intrigued by the notion of eating like a caveman, give the paleo diet a try and see if it takes—eating nutrient-rich whole foods, fiber-rich vegetables, and grass-fed meat got us this far, after all.